Low-lying states of odd-even <i>N</i> = 79 isotones within the nucleon-pair approximation*

Abstract In this paper, we study low-lying states of odd-even isotones, including , , , , and , within the nucleon-pair approximation (NPA) of the shell model. Low-lying energy levels of these nuclei with both positive and negative parities, as well as transition rates and g factors of some low-lying states, are calculated. Most of them agree closely with experimental data. The wave functions of yrast , , , states and negative parity and states of these nuclei are discussed in detail. The NPA calculations show that many of these states have a simple structure in the nucleon-pair basis.